// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/view_targeter.h"

#include "ui/events/event_target.h"
#include "ui/views/focus/focus_manager.h"
#include "ui/views/view.h"
#include "ui/views/view_targeter_delegate.h"

namespace views {

ViewTargeter::ViewTargeter(ViewTargeterDelegate* delegate)
    : delegate_(delegate)
{
    DCHECK(delegate_);
}

ViewTargeter::~ViewTargeter() { }

bool ViewTargeter::DoesIntersectRect(const View* target,
    const gfx::Rect& rect) const
{
    return delegate_->DoesIntersectRect(target, rect);
}

View* ViewTargeter::TargetForRect(View* root, const gfx::Rect& rect) const
{
    return delegate_->TargetForRect(root, rect);
}

ui::EventTarget* ViewTargeter::FindTargetForEvent(ui::EventTarget* root,
    ui::Event* event)
{
    View* view = static_cast<View*>(root);

    if (event->IsKeyEvent())
        return FindTargetForKeyEvent(view, *static_cast<ui::KeyEvent*>(event));

    if (event->IsScrollEvent()) {
        return FindTargetForScrollEvent(view,
            *static_cast<ui::ScrollEvent*>(event));
    }

    if (event->IsGestureEvent()) {
        ui::GestureEvent* gesture = event->AsGestureEvent();
        View* gesture_target = FindTargetForGestureEvent(view, *gesture);
        root->ConvertEventToTarget(gesture_target, gesture);
        return gesture_target;
    }

    NOTREACHED() << "ViewTargeter does not yet support this event type.";
    return NULL;
}

ui::EventTarget* ViewTargeter::FindNextBestTarget(
    ui::EventTarget* previous_target,
    ui::Event* event)
{
    if (!previous_target)
        return NULL;

    if (event->IsGestureEvent()) {
        ui::GestureEvent* gesture = event->AsGestureEvent();
        ui::EventTarget* next_target = FindNextBestTargetForGestureEvent(previous_target, *gesture);
        previous_target->ConvertEventToTarget(next_target, gesture);
        return next_target;
    }

    return previous_target->GetParentTarget();
}

View* ViewTargeter::FindTargetForKeyEvent(View* root, const ui::KeyEvent& key)
{
    if (root->GetFocusManager())
        return root->GetFocusManager()->GetFocusedView();
    return NULL;
}

View* ViewTargeter::FindTargetForScrollEvent(View* root,
    const ui::ScrollEvent& scroll)
{
    gfx::Rect rect(scroll.location(), gfx::Size(1, 1));
    return root->GetEffectiveViewTargeter()->TargetForRect(root, rect);
}

View* ViewTargeter::FindTargetForGestureEvent(View* root,
    const ui::GestureEvent& gesture)
{
    // TODO(tdanderson): The only code path that performs targeting for gestures
    //                   uses the ViewTargeter installed on the RootView (i.e.,
    //                   a RootViewTargeter). Provide a default implementation
    //                   here if we need to be able to perform gesture targeting
    //                   starting at an arbitrary node in a Views tree.
    NOTREACHED();
    return NULL;
}

ui::EventTarget* ViewTargeter::FindNextBestTargetForGestureEvent(
    ui::EventTarget* previous_target,
    const ui::GestureEvent& gesture)
{
    NOTREACHED();
    return NULL;
}

} // namespace views
